Circular saw blades are used to make longitudinal cuts through logs. The saw blades must have a large enough diameter or cut capacity to cut completely through the log from top to bottom. The saw cut capacity is defined by the diameter of the saw blade and the amount of saw blade that extends above a given work surface. For example, a circular saw blade typically contains an upper portion that extends above a support surface or table. The upper portion of the saw blade that actually cuts into the log of work piece is defined as the saw blade work surface and the distance from the top of the table, or the lowest location on the saw blade that actually cuts into the wood, to the top of the saw blade is defined as the saw blade cut capacity.
To prevent bending, saw blades are often supported, guided, or stabilized with guides. The guides are typically located on the lower half of the circular saw blade underneath the table that supports the log or board while being cut. Historically guides have not been positioned in the working surface of the saw blade that extends above the table and through the wood since the guide would restrict the cut capacity of the saw.
Regardless of where guides are normally located, there is a segment of rotational travel along the outside edge of the saw blade where no guidance is provided. Depending upon how far the circular saw blade extends above the table, the segment of the saw blade actually cutting into the wood at any one time can include up to a 180 degree segment of the saw blade. Throughout this range, or arc of unsupported rotation, the saw blade has a tendency to vibrate and move away from a preexisting desired alignment. Saw blade vibration and movement create rougher cut surfaces on the wood product and wedge shaped and other improperly sized boards that are either too thick or too thin. The problems with saw blade vibration and movement become worse the thinner the saw blades.
For deeper cuts (i.e., cuts that cut further into the wood), the saw blade cutting capacity must be increased by using either a larger diameter saw blade or by extending a greater portion of the saw blade above the log support table. Larger saw blades, however, have a greater width to retain enough rigidity so that the saw blade does not bend or vibrate as described above. Wider saw blades, however, cut a wider kerf that reduce the amount of usable wood product extractable from the log or board.